Evaluating the amount of water that passes through unmonitored inundation areas aside rivers is a major objective of hydrological modelling in the great tropical basins. In this study, we present a methodology based on satellite data only to evaluate such amount in the Curupira Lake, in the Amazon basin. We used the ESA’s ERS-2 and ENVISAT radar altimetry to determine the water stages in the Lake. The temporal resolution of these missions is 35 days. We used weekly mosaics of MODIS images, at 500m resolution, to compute inundated surfaces. We processed the MODIS images by computing three classes, namely vegetation, inundated forest and open water, on the basis of the NDVI and EVI indices. From this classification, we compute the wet surface as the sum of the open water and inundated forest classes. The study spans between years 2001 to 2008. As a result, we present the stagesurface relationship in this lake that can be used to compute the variations in water volume throughout the hydrological cycle.